Tube coupling



FIG. 1 is a right side upper perspective view in a released position showing our new design of the tube coupling;

FIG. 2 is a right side upper perspective view in a clamped position showing our new design of the tube coupling;

FIG. 3 is a left side lower perspective view in a released position showing our new design of the releasable tube coupling;

FIG. 4 is a right side elevation view in a clamped position showing our new design of the tube coupling; and,

FIG. 5 is a right side elevation view in a released position showing our new design of the tube coupling. 

CLAIM We claim the ornamental design for a tube coupling, as shown and described. 